Continuous flow blood separator

ABSTRACT

Apparatus for separating whole blood into at least two fractional components and continuously returning at least one component thereof to the source of the blood. The apparatus includes supply means establishing continuous communication between the source and the separating means, the separating means including a high speed centrifuge with a rotating seal means permitting entry of the whole blood through a stationary portion and separation of the blood in the centrifuge with the various components of the blood being returned to the stationary portion of the seal means.

United States Patent Judson et al.

[151 3,655,123 1451 Apr. 11, 1972 54] CONTINUOUS FLOW BLOOD 2,705,4934/1955 Malmros et a1 ..23/258.5 SEPARATOR 3,332,222 241328 glattiichel..128/214 ,7 9 1 9 or ova ..23/258.5 1 Inventors Geqrge -J whlmey Pomt,3,073,517 1/1963 Pickelsetal ..233/32 EmllJ- Frelreich, HoustomTeX-3,145,713 8/1964 Latham .....128/214 73] Assignee: The United states ofAmerica as 3,195,809 7/1965 PlCkClS 8t 31.... ..233/21 represented bythe secretary, Dept. of 3,292,937 12/1966 Nunley ..233/21 X Health,Education & wenare 3,240,425 3/1966 Ray et al. ..233/27 X [22] Filed:July 30, 1969 Primary Examiner-Jordan Franklin Assistant Examiner-GeorgeH. Krizmanich [2]] Appl 8694l8 Att0meyHolman&Stern Related U.S.A 11 tData pp ca m 57 ABSTRACT [62] Division of Ser. No. 570,792, Aug. 8,1966, Pat. No.

3,489,145 Apparatus for separating whole blood into at least twofractional components and continuously returning at least one 52 us. 01..233/21 233/28 128/214 there The apparatus [51] lnt.C1 .Btl4b 11 00includes Supply means'establishing continuous communica' [58] FieldofSearch ..233/ 2 1 161A 2 22 '19 between the some and Farming means233/3 4 i 32 27 128/214 5 separating means including a high speedcentrifuge with a rotating seal means permitting entry of the wholeblood through a stationary portion and separation of the blood in the[56] References Cited centrifuge with the various components of theblood being TE S S PATENTS returned to the stationary portion of theseal means.

2,546,186 3/1951 Hall ..233/11 X 9Claims, 18 Drawing Figures 11 1G 4ANTl- 81 SALINE 5(,\SAL1NE COAG {B0 4 \OO 50 63 BUFFER 1 DONOR Y 65 10102,

X 84 104 84 f no U$ 5e l 107 l WASTE D\\I ERT \3. 0 R p wb be ACCENTRWUGE us BO\, 3/ PUMP I sguMP iixmfq 14 a 4 1 nre ptg ugsg flPatented April 11, 1972 7 Sheets-Sheet l INVENTORS GwQat 7 Jumm/ am J.rug/o/ i, TH'TORNEY wia Patentfl A ril 11, 1972 7 Sheets-Sheet 4 i 3 I Qw d/7 id 5 W 5 Sm H2 owe ATTORNEY Patented April 11, 1972 7 Sheets-Sheet5 15C: 5s I) A! INVENTOR5 Z vow BY v 264m 4 54 ATTORNEY I Patented April11, 1972 '7 Sheets-Sheet 6 ZNVENTOR Gab/26g rwas) LM L J 5&755/4/ ATTOR.N'E Y Patented April 11, 1972 3,655,123

7 Sheets-Sheet '7 /6. /8 I 6:. 5 {(0% [wi l [(0% J 6,48 I

PUSHFQR PUSH Pusmo Iv mm POWER- R ocuuneo BUBBLE Wm LOW NE D LY: NEEDLEm E m QEBET WASTE 0N DNERT VHN LOW UM- LEFT cemmwee RT. cemkzwuee RPM \oSYSTEM 0.9M x \o 50 \Q0 \50 7.00 G\ 50 \00 \S0 100 PRME 16 RUN . who 0RETURN FLOW RATE 6 x FLOW RATE TOTAL ML \NPUT mm m \NPUT PLASMA PUMP \ZbPUMP Wbc PUMP PUMP w INVENTOIB BY v lfukm,

ATTORNEY CONTINUOUS FLOW BLOOD SEPARATOR This application is adivisional application of copending application Ser. No. 570,792, filedAug. 8, 1966, now U.S. Pat. No. 3,489,145, granted Jan. 13, 1970.

This invention relates to apparatus for separating or fractionatingwhole blood into its various individual components and more particularlyit relates to a method, means, unit and system for accomplishingseparation or fractionation under the influence of centrifugal force.

cells and platelets, and some of these fractions are returned to thehuman donor while others of the fractions can selectively be collectedfrom the machine. As such, it may be stated that the present inventionrelates to an in vivo type unit wherein blood is taken from a livedonor, is passed through the machine, and is then returned to the donor.

To appreciate the nature of the present invention, as well as thedifficulties and complications necessarily inherent in any unit such asthat described hereinafter, one must first understand the nature andcharacter of whole blood itself. Blood is a tissue composed of a seriesof cells suspended in plasma. Approximately 45 percent of the volume ofblood is formed by these cells, while the remaining 55 percent of thevolume of blood is the plasma. Plasma essentially is the fluid part ofthe blood which suspends the cells and plasma itself is formed as asolution of approximately 92 percent water, 7 percent proteins and theremaining 1 percent of various mineral salts.

The blood cells which are suspended in the plasma include red cells,also referred to as erythrocytes, white cells also referred to asleukocytes, and platelets. The present invention not only separates thecells from their suspension in the plasma, but additionally, serves toseparate the individual types of cells themselves, and for this reason,it is important to further understand the specific nature, function andproperties of each of the aforementioned types of cells.

The red cells or erythrocytes are small solid particles containing thesubstance hemoglobin, a chemical substance having a high degree ofaffinity for oxygen and carbon dioxide. Accordingly, the main functionof the red cells is to transport oxygen from the lungs to the bodytissues and to transport carbon dioxide from the body tissues to thelungs. The red cells are created by the bone marrow of the body andvirtually all of a persons red cells are within his blood stream. Thereare approximately 5,000,000 red cells for each cubic mm of blood witheach red cell having a specific gravity of approximately 1.1. The redcell survival or that period of time in which a red cell is able toperform its function within the body, is approximately 120 days. Afterthis period of time, these exhausted red cells are removed from the bodycirculatory system and destroyed. Naturally, even while these exhaustedred cells are being destroyed, new red cells are being created andintroduced into the circulatory system.

Considering now the white cells or leukocytes, such cells generallyserve a protective function within the blood stream, and there are, infact, several different varieties of white cells, each of which serves sspecified function. One major variety of white cells are thegranulocytes, with this variety forming between 60 and 70 percent of thetotal white cells. Granulocytes are initially formed by the bone marrowand act as a defensive mechanism which counteracts the bacteria or otherforeign substance. Granulocytes have a specific gravity of approximately1,057, somewhat less than that of the red cells, and only about 5,000granulocytes are contained in each cubic mm of blood. The other commonvariety of white cells are the lymphocytes which are initially formedby' the body lymph glands and which comprise about 30 to 40 percent ofthe white cells. The main function of the lymphocytes is to participatein the production of antibodies to thereby prevent the spread ofinfection throughout the body and to aid, to some degree, in developingimmunity. There are only about 2,000 lymphocytes per cubic mm of bloodand the specific gravity of these lymphocytes is somewhere between thatof the red cells and the granulocytes. There are other varieties ofwhite cells present in very minor amount in the blood stream, such asmonocytes, eosins and basophils, but these minor varieties need not bediscussed in any detail herein.

Finally, platelets are small colorless bodies which act as a source ofthromboplastin and thereby serve the function of aiding in the clottingof blood. Platelets are derived from megakaryocytes which are producedby the bone marrow and released therefrom into the blood stream tocontrol hemorrhage. A platelet has a specific gravity of approximately1.01 and there are about 200,000 platelets per cubic mm of blood.

With the foregoing explanatory matter in mind, it becomes apparent thateach of these various components of blood has its own physical andchemical properties and serves its own particular function. Accordingly,it should be appreciated that it is highly desirable to separate wholeblood into these various individual fractions, for a variety ofdifferent purposes. In particular, it is desirable to produce yields ofwhite cells for use in blood research and experimentation, immunologystudies and for clinical use in organ transplants. Similarly, it is ofclinical importance to produce a yield of white cells to be used as supportive therapy for cancer patients whose own white cells have beendepressed by the use of anticancer drugs. Along the same line, it mustbe recognized that a patient suffering from leukemia has a very highwhite cell count and treatment of such patient often centers aboutremoval of the excess number of white cells from the patient. Insofar asplatelets are concerned, it is desirable to produce a yield of plateletsto aid in study and supportive therapy with regard to the coagulationprocess. As to the collection of plasma, the uses of fresh and frozenplasma are well known for use in transfusion techniques. Finally, withrespect to red cells, it is desirable to produce pure red cell yieldsfor use in transfusing fresh packed red cells and for preservation byfreezing.

There are certain known techniques and types of equipment for separatingor fractionating whole blood directed to an in vitro" type of operationwherein a quantity of blood is processed after the same has been removedcompletely from a donors circulatory system. In such known in vitro"techniques and procedures, such as plasmapheresis and leukapheresis, theyield of white blood cells is, at best, very low, and moreover, suchexisting techniques and procedures are extremely complicated, laboriousand time consuming. Thus, until the present time and the development ofthe present invention, there has been no practical and rapid method forremoving white blood cells from a quantity of whole blood. Similarly,there has been a need for an efficient and safe equipment, technique orother means for a continuous flow in vivo type of blood separation.

Perhaps the need for the present invention can best be understood byconsidering the commonest form of in vivo blood transfer, namely, ablood transfusion from a donor to a recipient. Virtually all of thedonors red cells or erythrocytes are in his blood stream and can thus bereadily transfused to the recipient. About to percent of the transfusedred cells will remain in circulation in the recipient. Also, aspreviously indicated, the red cell survival is about days, and thus, ifthe recipient only requires additional red cells, he need only receivetransfusion at widely spaced intervals. Furthermore, short termpreservation techniques for red cells have been perfected and such redcells can thus be stored for up to three weeks and still remaineffective.

On the other hand, when platelets are transfused from a donor to arecipient, only approximately 33 percent and often less thereof, remainin circulation in the recipient. Also, platelet survival is one to threedays, and accordingly, transfusion must be given quite frequently.Finally, there is no known preservation technique for platelets, so onlyfreshly drawn platelets can be used. Thus, it can be seen that platelettransfusion is considerably more difficult and expensive than red celltransfusion, but it is at least possible.

However, considering white cell or leukocyte transfusion, until theadvent of the present invention, there was no known convenient andefficient means for accomplishing this type of transfusion. This will bemore clearly understood when it is recognized that less than percent ofthe donors white cells are contained within his circulating bloodstream. The remainder, somewhat near 80 percent of the white cells, arecontained within the bone marrow or lymph nodes. Thus, in any event, atransfusion of whole blood from a donor to a recipient is a rather poorsource of white cell supply. Accordingly, in the transfusion of wholeblood from a normal donor to a recipient, there is no measurableincrease whatsoever in the recipients white cell count. In fact, testshave shown that to obtain any appreciable increase in a recipients whitecell count would require more than twice the number of white cellscontained in the normal donors entire blood volume. Also, white cellsurvival is very short and thus even if it were possible to provide therecipient with a transfusion having an adequate number of white cellstherein, such as a transfusion from a donor suffering from chronicmyelocytic leukemia, the survival time of the transfused white cellswould be very short, and a further transfusion would then be needed.

As a final point with respect to transfusion from a donor to arecipient, it is generally known that a donor who has whole bloodremoved from his circulatory system can donate only one unit or 500 ccof blood every 60 days. This is primarily because the red blood cells,which have a very long life span, are normally replaced at a very slowrate. Therefore, if a person donates whole blood more frequently thanevery 60 days, he may develop anemia or low concentration of red cellsin his blood. However, if whole blood is removed from the donor and thered cells alone are returned to the donor, such donor can donate 1 literof plasma, the equivalent of four 500 cc units of blood, every week. Inother words, the person can donate plasma more than 30 times asfrequently as he can donate whole blood. This results because theplatelets and the plasma proteins, the liquid portion of the blood, arereplaced by the donors body much more frequently than are the red cells.Since the body replaces white blood cells most rapidly, the presentinvention provides a valuable unit since it separates the white cellsfrom whole blood and returns the red cells, plasma, and, if desired,platelets, to the donor, thereby greatly increasing the permissiblefrequency of white cell donations.

Before development of the present invention, it was believed that theproblems in creating an in vivo type of blood separator were virtuallyinsurmountable. It must be remembered that in a separator of this type,the donors blood is continuously flowing out of his body, is beingseparated, then recombined, and finally returned to his body. Naturally,any damage to the blood during transit through the separating apparatuscould result in serious injury or even death to the patient. Therefore,a great variety of safety factors had to be considered in developing thepresent invention as a practical, safe and reliable piece of equipment.

Foremost among the problems encountered in developing the presentapparatus, was a consideration of what would occur if the machine powersuddenly failed. The present invention had to be designed in such amanner that even if such power failure did occur, the same would not beinjurious to the donor and the donor would not lose too great a quantityof his blood.

Another problem was the consideration of the tendency of blood to clot,and for this reason, provision had to be made for continually admixinganti-coagulant with the blood to assure that the same would flow readilythrough the separating apparatus. Also, in this regard, a sensingmechanism had to be provided to assure that the supply of anti-coagulantwill not inadvertently become exhausted, thereby permitting the blood toclot. Of course, another serious problem in any apparatus of this typeis that of sanitation, and the present invention had to be particularlyconcerned with the fact that no impurities contacted the blood duringits travel through the separation apparatus. To accomplish the desireddegree of sanitation, the

present invention was designed with no air blood interface, so that theblood would contact only clean sterile surfaces.

Other problems in the development of an apparatus of this type had to beconcerned with the possibility of undue temperature rise in the bloodduring its travel through the apparatus, as, for example, due to theheat of friction created at bearing seals and the like. Along a similarline, since the blood was to be out of the patients body for some timeduring its transit through the apparatus, such blood had to be restoredto proper temperature before being returned to the patients body. Also,means had to be provided to sense if any vein occlusion occurred,thereby interrupting the flow of blood from the patient to theapparatus, and simultaneously, causing damage to the donor and the vein.Another problem which had to be considered was the problem of hemolysisof the red cells during their travel through the machine. It was fearedthat the passage of the red cells through pumps and through a centrifugeapparatus would damage the red cells, and this was one of theconsiderations which had to be taken into account in design of theapparatus. Finally, there was the problem of leakage of air into theblood as the same was outside the donors body, thereby creatingpotentially fatal bubbles in the blood stream.

With the foregoing matters in mind, it is, therefore, the principalobject of the present invention to provide a continuous flow bloodseparator which can be linked with a live patient to accomplish acontinuous in vivo separation of human blood.

Another principal object of the present invention is to provide a methodand means for separating whole blood into its major fractionalcomponents as such whole blood is being continuously supplied from alive patient.

Another principal object of the present invention is to capitalize onthe differences in specific gravity between the major components ofwhole blood by using such differences in specific gravity to effect aseparation of the components into individual fractions.

Another principal object of the present invention is to provide amethod, means, unit and system capable of drawing whole blood from alive patient, dividing such whole blood into its major fractionalcomponents, removing selected fractional components from the remainderthereof and thereafter recombining the remaining fractional componentsand returning the same to the patients circulatory system, all of theforegoing being carried out on a continuous flow basis.

Another object of the present invention is to provide a practicalequipment means which can process whole blood on an in vivo basis with aminimum amount of effort and transportation of the blood beingencountered during such processing.

Other objects of the present invention include the provision of aninstrument wherein: (a) leukocytes are separated from whole blood at areasonable efficiency be sedimentation in a centrifuge; (b) operation isconducted on a continuous flow basis to allow processing of largequantities of blood at optimal speed and efficiency; (c) a vein-to-veinprocedure is used to avoid arterial puncture; (d) an anti-coagulant thatdoesnt require anti-coagulation of the donor, and risks associatedtherewith, is employed; (e) the loss of platelets, red cells and plasmais minimal to allow processing of large volumes of blood in a singledonor; (f) a completely closed needle-tomeedle system is used, withoutany air-blood interface, to obviate the danger of air injection orbacterial contamination; (g) the entire system contains a volume ofblood v less than 500 milliliters at all times; and (h) the system canbe easily cleaned, mostly disposable, and sufficiently automated to beoperated by a single nonprofessional operator.

Further objects of the present invention include the provision of amethod and means for accomplishing continuous in vivo separation ofwhole blood, which method and means: (a) efficiently separates wholeblood into its major fractional components, namely, red cells, whitecells, platelets and plasma; (b) enables any selected major fraction orfractions of the separated blood to be collected while the remainingfractions can be returned to the donors circulatory system; (c)

produces high yields of white cells and platelets which were heretoforeonly obtainable in small quantities; (d) includes a variety of safetyfactors to ensure that neither the patient nor his blood will be bannedin any way, even if machine failure 'were to occur; (e) operates in anefficient, economic manner blood to the donor on a continuous basis; (c)collects the whole blood from the donor in a weight-sensitive receptaclemeans which automatically controls the commencement and termination ofblood withdrawal from the donor; (d) continuously provides blood fromthe receptacle means to a centrifugal separator in which, due to thedifferences in specific gravity in the parts of the whole blood, suchwhole blood is separated into major fractional components; (e) permitsselected fractional components of the blood to be drawn off from thecentrifugal separator while the remaining fractions thereof arerecombined for return to the donors body; (f) automatically backfeeds aportion of the blood returning to the donors body from the centrifugalseparator during the time periods when no blood is being withdrawn fromthe donors body, to thereby prevent any undesired clotting at the donorneedle; (g) automatically senses any vein occlusion and in the eventthat such does occur, automatically stops blood withdrawal to preventany damage to the patient or his vein; (h) automatically collects anyair bubbles from the recombined blood stream returning to the patientsbody; and, if desired (i) re-heats the returning blood stream until thesame is at proper body temperature, thereby eliminating any possibilityof trauma or shock to the donor when the blood re-enters his body.

Still another object of the present invention is the provision of acontinuous flow blood separator having a variety of safety devicesincluded therein to prevent any damage to the patient and/or his blood,such safety devices including the provision of: (a) highly steriletransfer tubing which maintains full sanitary conditions whilecontacting the blood; (b) gradually increasing the donor flow rates tominimize the occurrence of an occluded vein; (c) minimizedtransportation of the blood to decrease the time that the blood isoutside the donors body; (d) minimized volume of the apparatus to assurethat only a small volume of the patients blood will be outside his bodyin the event that the machine should shut down due to power failure; (e)means for sensing vein occlusion and for automatically terminatingwithdrawal of blood from the donors body, should the same occur; (f)level sensing means to assure that the intravenous saline solutions andthe anti-coagulant solution do not inadvertently drop below a specifiedsafe level; (g) specialized seal arrangements within the machine tominimize the amount of temperature rise due to heat of friction and thelike, and to prevent hemolysis and the ingestion of air into the system;(h) an automatic diverting arrangement to prevent the blood frominadvertently clotting before the same is mixed with anti-coagulant; (i)means for detecting and collecting any bubble which might have formed inthe blood before the same is returned to the donors body; (j) means forre-heating the blood to the proper level before the same isre-introduced into the donors body; (k) an automatic saline primediverting arrangement to prevent priming solution from being returned tothe donors body, except when so desired; and, (1) visual and audiblesignal means on the apparatus to immediately indicate any unsafecondition to the operator.

Other objects, advantages and salient features of the present inventionwill become apparent from the following detailed description, which,taken in conjunction with the annexed drawings, discloses a preferredembodiment thereof.

The foregoing objects are generally attained by providing an apparatusor system of the type to be described in detail hereinafter, whichapparatus or system is linked with a donor by needles inserted into thedonors limbs, as, for example, an output needle inserted into one of thedonors arms and a return needle inserted into the other of the donorsarms. Initially, the system is primed with a saline solution to purgeany air therefrom, and after such priming has been effected, an armcufi' is inflated by the machine on the donors arm carrying the outputor supply needle. Simultaneously with expansion of the arm cuff, a firstpump is energized to initiate withdrawal of blood from the patients arm,and also simultaneously, a second pump is energized to supplyanti-coagulant which is mixed with the donors blood. Thisanti-coagulated blood is then supplied to a receptacle means, also knownas a buffer bag, and the same becomes gradually filled withanti-coagulated blood. Once this buffer bag has been filled, a sensingdevice automatically shuts off the blood and anticoagulant pumps anddeflates the arm cuff, thereby temporarily terminating withdrawal of theblood from the donors arm and permitting the donor to rest.

The anti-coagulated blood from the buffer bag is then continuously fedto a centrifugal separator which operates to separate or fractionate theblood into its major fractional components, namely, red cells, whitecells, platelets and plasma. A separate output port is provided for eachof these fractional components, except the white cell port is used tocollect platelets, and a separate pump is linked with each of theseports, whereupon when a selected pump is energized at a specified rate,the same will draw a selected fraction of blood through its associatedport and will pull the withdrawn fraction through .the pump at thespecified rate.

The red cells exit from the centrifugal separator and pass throughreturn tubing to the return needle located in a vein in the donors otherarm. A waste divert arrangement is provided in the return tubing toselectively exhaust certain products, such as the priming solution,rather than letting such products return to the donor. A bubble detectoris provided in the return line to detect and collect any bubbles whichmight inadvertently have been caused in the red cell stream. Also, aheater is provided for bringing the returned red cells back to normalbody blood temperature. The plasma can be recombined with the red cellsin advance of the bubble detector and return heater, and can be returnedto the donors body with the red cells. Alternatively, the plasma may bepassed to a needle rinse arrangement which feeds the plasma back to ashort length of tubing between the output needle and the junction wherethe anti-coagulant is mixed with the blood coming from the donors body.This plasma return will prevent any undesired clotting within the shortlength of tubing. As an ancillary feature, the plasma, which usually isrich with platelets when G forces are low, may be passed through asecond stage centrifuge which can separate the platelets from the plasmato permit ultimate collection of the platelets themselves.Alternatively, concentrated platelets can be collected at higher Gforces directly through the white cell port.

When the level of anti-coagulated blood in the buffer bag drops to apreselected level, a sensing mechanism automatically re-inflates the armcuff and energizes the blood and anticoagulant pumps to once again startwithdrawal of blood from the donor. Such withdrawal will again continueuntil the buffer bag is filled, at which time, the arm cuff will againbe deflated and the blood and anti-coagulant pumps will again bestopped. The withdrawal from the donor is thus intermittent, but thefeed from the buffer bag to the centrifugal separator is constant, andlikewise, the return flow of blood to the donor is constant.

Referring now to the drawings:

FIG. 1 is a schematic view of the system of the present invention;

FIG. 2 is a top plan view of a separator machine embodying the system ofthe present invention;

FIG. 3 is a front elevational view of the machine of FIG. 2;

FIG. 4 is a rear elevational view of the machine of FIG. 2;

FIG. is a sectional view of the novel centrifuge means of the presentinvention;

FIG. 6 is a top plan view of the filler piece used in the centrifugemeans of the present invention;

FIG. 7 is a top plan view of a rotating seal used in the centrifugemeans of the present invention;

FIG. 8 is a sectional view taken along line 88 of FIG. 7;

FIG. 9 is a side elevational view of a stationary seal used in thecentrifuge means of the present invention;

FIG. 10 is a bottom plan view of the stationary seal of FIG.

FIG. 11 is a sectional view taken along line 1111 of FIG. 10;

FIG. 12 is a top plan view of a typical pump means used in the presentinvention;

FIG. 13 is a fragmentary sectional view of the pump means of FIG. 12;

FIG. 14 is a perspective view of one type of pump drive means used inthe present invention;

FIG. 15 is a perspective view of another type of pump drive means usedin the present invention;

FIG. 16 is a side elevational view of a typical valve means used in thepresent invention;

FIG. 17 is a sectional view of the novel bubble detector used in thepresent invention; and

FIG. 18 is a front elevational view of the novel control panel andwarning light assembly used in the present invention.

Referring now to FIG. 1, which represents a simplified schematic diagramof the overall system of the present invention, it will be seen that adonor or patient generally designated 50 is linked through a series oflines and components with a centrifuge generally designated 52. Theentire objective of the present invention is to supply whole blood fromthe donor 50 to the centrifuge 52 wherein separation will occur due todifferences in rates of sedimentation and density, within a centrifugalfield. Thus, the centrifuge 52 separates the whole blood from thepatient 50 into red cells or erythrocytes, white cells or leukocytes,platelets and plasma. The platelets are drawn out of the centrifuge 52either with the white cells or with the plasma in the form ofplatelet-rich plasma. Certain of these blood fractions, such as thewhite cells, can be separately collected from the centrifuge 52, whilethe remaining fractions leave the centrifuge 52, are recombined and arethereafter returned to the donor 50. Thus, the centrifuge 52 effectivelyis coupled with and acts as a portion of the donors own circulatorysystem. It may be thus stated that the present invention relates to anin vivo system having continuous flow characteristics. The termcontinuous flow will be understood to be applicable in the presentinvention even though blood is only intermittently withdrawn from thedonor 50, but is continuously returned to him. This continuous flow invivo type of operation should be recognized as wholly distinct fromprior art in vitro techniques and prior in vivo techniques such as theConn F ractionator, wherein a quantity of blood was entirely withdrawnfrom a donors body and separated from the remainder of his circulatorysystem, and was thereafter separated or otherwise processed apart fromthe donor himself.

While the centrifuge 52 acts as the main fractionating or separatingmechanism of the subject invention, a second centrifuge 54, as shown indotted lines in FIG. 1, may likewise be provided to enable the system tobe used in two stage procedures wherein further subdivision orconcentration of a particular blood fraction may be required.

In describing the system of the present invention hereinafter, it willbe understood that the tubing, centrifuge bowls and centrifuge faceseals may be provided as disposable items which can be discarded aftereach use of the system. In this manner, the problems of sterilizationare greatly diminished.

Electrocariogram apparatus is installed near the donor 50 to enable theoperator to periodically monitor the donors heart condition and toobserve the effects of anti-coagulant on the action of the heart muscle.Appropriate venipunctures are made in the donors limbs, and in the mostusual instance, an output needle is linked with one of the donors armsand a return needle is linked with the other of his arms. The outputpoint is designated X in FIG. 1, while the return point is designated Yin FIG. 1. Before the donor is actually linked with the system of thepresent invention to initiate separation of his blood, it is firstnecessary to prime the system in order to purge any air therefrom. Suchpriming is effectuated through use of an isotonic saline primingsolution, supplied by a source generally designated 56 in FIG. 1. Tounderstand the nature of the priming operation, it will first benecessary to generally describe the other major components of the systemof the present invention. The major components include five separatepumps which provide the force within the system to convey whole blood,red cells, white cells, plasma and anticoagulant through the variouslengths of tubing interconnecting the donor 50 with the centrifuge 52.More specifically, these pumps include an anti-coagulant pump generallydesignated 58 and normally coupled with a supply of anticoagulantgenerally designated 60, a whole blood pump generally designated 62linked between the donor and a receptacle means or reservoir generallydesignated 64 having an inlet 63 and an outlet 65, such reservoir alsobeing referred to as a buffer bag. Additionally, the system includes ared cell pump generally designated 66, a white cell pump generallydesignated 68 and a plasma pump generally designated 70, all of theselatter pumps being connected to outputs of the centrifuge 52.

To initiate the priming operation, the centrifuge 52 is started at slowspeed and the anti-coagulant pump 58 and blood pump 62 are energized,the latter being set to draw the saline 56 into the system at a rate ofabout milliliters per minute. As this saline priming solution enters thebuffer bag 64, the same will start to fill and when this bag is betweenonethird and one-half full, the output pumps 66, 68 and 70 are eachstarted to draw an output at the rate of 25 to 30 milliliters perminute. Thus, the saline priming solution will transfer from the bufferbag 64 into the centrifuge 52 and since the priming fluid has a higherspecific gravity than the air, the same will displace any air within thecentrifuge. That is, the priming fluid will collect on the outermostportion of the centrifuge walls thereby forcing any air inwardly towardthe center of the centrifuge. The operator conducting the priming of thesystem visually observes the output from the centrifuge to the variousoutput pumps. When he observes saline in the line leading to the whitecell pump 68, this pump is turned off. When the saline in the lineleading to and past the red cell pump 66 reaches the point designated R,where the plasma ordinarily recombines with the red cells, the operatorthen turns off the red cell pump 66.

The priming solution exiting from the centrifuge through the plasma linepasses the plasma pump 70 and is supplied to a needle rinse mechanismgenerally designated 72, which will be described in further detailhereinafter. This mechanism 72 includes a pair of oppositely actingvalves 74 and 76. That is, when the valve 74 is open, the valve 76 isclosed, and vice versa. As the priming is being carried out, themechanism 72 is set for a needle rinse, thus meaning that the valve 74is opened and the valve 76 is closed. The saline priming solution willthus flow through the valve 74 and upwardly, as indicated by the arrows,toward the output side X of the donor 50. This operation purges the airfrom the donor line. When such purging has been completed, the needlerinse mechanism 72 is shut off, thereby opening the valve 76 and closingthe valve 74. The priming solution will then pass through the valve 76to the recombination point R and will continue through the return linetoward the return side Y of the donor. The priming solution finallyreaches the return point Y of the donor, and when this occurs, thereturn line will have been completely purged of air. At this time, thepriming solution can be diverted through a waste divert assemblygenerally designated 78 to an exhaust means generally designated 80.

At this time, the entire system will be filled with priming solution andall air will be purged therefrom. Accordingly, the donor 50 can then belinked with the system to enable whole blood to enter the system.Because the whole blood has a higher specific gravity than that of thepriming fluid, the whole blood introduced into the system will serve todisplace the priming fluid, just as the priming fluid itself served todisplace any air previously within the system.

As the system is set into normal operation, an intravenous saline supply82, linked with the return line, is turned on at a slow drip. Aninflatable arm cuff means generally designated 84, surrounds the donorsarm near the output point X. A short length of tubing generallydesignated 86 extends from the output point X to a junction 1 where theanti-coagulant from the supply 60 is admixed with the whole bloodflowing from the donor. The centrifuge 52 is gradually brought up tooperating speed, the arm cuff means 84 is expanded, and theanti-coagulant pump 58 and blood pump 60 are started into slowoperation. The pumps 58 and 62 are geared together for synchronousoperation, and as these two pumps operate, blood is drawn from thedonors arm through the length of tubing 86 to mix with theanti-coagulant coming from the supply 60 thereof, such mixing takingplace at the juncture point J. The gearing arrangement between the pumps58 and 62, is such that a predetermined volume ratio of blood toanticoagulant is maintained, for example, a 7:1 ratio. Theanticoagulated blood then flows from the juncture J through a line 88and to the buffer bag 64. The speed of the blood pump 62 is slow atfirst to prevent occlusion of the donor vein, but this pump graduallyincreases in speed up to a maximum flow rate of 100 milliliters perminute. The volume of the buffer bag means 64 is about 150 millilitersand the volume of the centrifuge 52 is about 125 milliliters. All of thevarious other components, tubing, and other parts of the systemaccommodate about 140 milliliters, so that even when the system isentirely filled with blood, the total quantity of blood outside thedonors body is only about 415 milliliters. The average 150 lb. personhas about 6,000 milliliters within his circulatory system while theaverage 200 lb. person has about 7,600 milliliters within hiscirculatory system, so it can be seen that the total quantity of bloodoutside the donors circulatory system at any one time is rather small.The system of the present invention is purposely designed in thismanner, so that in the event of any power failure, the donor 50 will notlose any more blood than is normally given during a conventional bloodtransfusion.

Level control means to be described in further detail hereinafter, areassociated with the buffer bag 64 to sense when the same is filled andto further sense when the level therewithin drops to a specified point.Once the anti-coagulated blood flowing through the line 88 fills thebufier bag to a predetermined level, the system automatically deflatesthe arm cuff means 84 and stops the pumps 58 and 62. This allows thedonor 50 to rest while the anti-coagulated blood from the buffer bag 64drains into the centrifuge 52. However, once the pumps 58 and 62 havestopped, there is a danger that the blood within the tubing 86, betweenthe output point X and the junction J, will clot, due to the fact thatno anti-coagulant is mixed therein. To prevent clotting from occurringwithin this length of tubing 86, the needle rinse mechanism 72 isoperated to open the valve 74 so that priming fluid will passth'erethrough and up to and past the junction J. This priming fluid isused during the initial operation of the machine to prevent clottingwithin the tubing 86; however, after the machine has been in operationfor a few minutes, all of the priming fluid has been exhausted from thesystem and the donors own plasma is utilized for subsequent needle rinseoperation.

When the buffer bag 64 is initially filled with anti-coagulated blood,the operator must make sure that the pumps 66 and 70 are turned on.Naturally, the plasma pump 70 has to be utilized to accomplish theneedle rinse operation described immediately hereinabove. Theanti-coagulated blood from the bufier bag drains by gravity from outlet65 through a line generally designated to the centrifuge 52. The wholeblood enters the centrifuge 52 through a seal means and the action ofthe output pumps 66 and 70 causes this blood to move into a centrifugalfield set up by the rotating centrifuge. The centrifugal forces withinthe separator cause the whole blood to climb along the walls of thecentrifuge and to simultaneously separate into fractions based mainlyupon differences in specific gravities of the various componentialportions of the whole blood. The fraction having the heaviest specificgravity is the red cells or erythrocytes and this fraction is the onecontained on the outermost wall of the centrifuge 52. The next heaviestand hence next inwardly displaced fraction is the white cells orleukocytes, then come the platelets and finally the innermost orlightest layer is the plasma. The top cover of the centrifuge 52 isfabricated of transparent material so that the whole blood separationwithin the centrifuge 52 can be visually observed. Such a visualobservation of the separation would show the outermost red cell fractionto be of a dark red color, the center or middle white cell and/0rplatelet fraction to be of a pinkish or white color, commonly called thebuffy coat, and the innermost plasma fraction to be of a yellowishcolor.

The saline previously contained in the centrifuge 52 is moved out aheadof the blood being separated and is diverted to the waste divertmechanism 78. Separate output ports are provided in the centrifuge 52,one for the red cells, one for the white cells and one for the plasma.The platelets can be drawn out either through the white cell port or theplasma port. As the centrifuge is initially filling, the red cells areallowed to accumulate along the outer wall thereof by turning off thered cell pump 66, but the plasma pump 70 remains in operation so thatthe plasma is continuously drawn out from the centrifuge 52. When theinterface between the red cell and the plasma reaches the white cellport, the red cell pump 66 is turned on and the pumps 66 and 68 areadjusted relative to one another to maintain such interface in alignmentwith the white cell port. The return rate of the red cells and plasma tothe donor is about 50 milliliters per minute. Assuming that no needlerinse is occurring, the plasma will combine with the red cells at therecombination point R and such recombined plasma and red cells will thentraverse the return line generally designated 92 toward the waste divertassembly 78.

The waste divert assembly 78 includes a pair of oppositely acting valves94 and 96. That is, the valve 94 is open when the valve 96 is closed,and vice versa. When the saline priming fluid is being exhausted fromthe system, the valve 94 is closed and the valve 96 is opened, therebydiverting the saline priming fluid through a line 98 to the exhaustmeans 80. However, once the priming fluid has been completely exhaustedfrom the system, the valve 96 is closed and the valve 94 is opened.Thereafter, the recombined plasma and red cells traversing the returnline 92 will pass through the valve 94 and continue toward the donorsbody.

The recombined flow of plasma and red cells then re-enters the donorsbody at the return point Y, and at this time, the intravenous drip fromthe saline supply 82 may be turned off.

Control of the amount of any one fraction being withdrawn from thecentrifuge 52 may be accomplished by varying the settings of the outputpumps 66, 68 and 70. Thus, if one wanted to increase the amount ofplasma in the centrifuge, the speed of the plasma pump 70 would beslowed down while the speed of the red cell pump 66 would be increased.Conversely, if one wanted to increase the amount of red cells in thecentrifuge, the speed of the red cell pump 66 would be slowed down andthe speed of the plasma pump 70 would be increased. Thus, by properlyregulating and correlating the speeds of the pumps 66 and 70, therelative radial location of the interface between the plasma and the redcells can be controlled.

lnsofar as the white cells are concerned, the volume of white cells innormal blood is only about 1 percent of the total. Accordingly, thewhite cell layer or bufiy coat within the centrifuge builds up slowlyand does not even become noticeable for sometime. Therefore, when thedonor 50 has normal blood, the white cells from the centrifuge 52 aredrawn out only at intervals, such drawing out occurring by operation ofthe white cell pump 68. On the other hand, if the donor 50 has a highwhite cell count, such as he would have if he were suffering fromchronic lymphocytic leukemia, the volume of white cells within the bloodwould be considerably higher and the same could be drawn outcontinuously at a slow rate of 2 to 4 milliliters per minute.

It will be recalled that the buffer bag 64 was initially filled withanti-coagulated blood, and when this blood reached the high level withinthe buffer bag, a sensing mechanism automatically deflated the arm cuff84 and terminated operation of the pumps 58 and 62. Thereafter, theblood from the buffer bag drained continuously by gravity through theline 90 to the centrifuge 52. This drainage of the blood from the bufferbag eventually operates a first low level signal device which serves tore-inflate the arm cuff 84, to start the pumps 58 and 62, and toterminate the operation of the needlerinse mechanism 72. As the pumps 58and 62 again start to operate, blood will again be drawn from the donor50 and transferred to the buffer bag 64, and the foregoing cycle willstart again. From this time on, operation of the system will becompletely automatic except in the event that the operator switches thered cell-plasma pumps into complementary mode. Such mode adjusts therelative red cell-plasma flow rates to keep the interface therebetweenat a constant radial position within the centrifuge, such position beingjust before the white cell port. Once the buffer bag is again filled tohigh level, the pumps 58 and 62 will stop, the arm cuff 84 will deflate,and the machine will again to into needle rinse. It can thus be seenthat donations from the donor 50 into the system are intermittent, inunits of approximately 150 milliliters each. This is done to permit thedonor to rest and to minimize the length of time that the cuff 84 isinflated. On the other hand, the return flow rate to the donor is about50 milliliters per minute and is maintained constant.

As was previously mentioned, a sensing mechanism is associated with thebuffer bag 64 to determine when the same reaches a predetermined high orlow level. To further understand this sensing mechanism, it will be seenfrom FIG. 1 that the buffer bag 64 is supported from one end of a beambalance arm means generally designated 100, such beam balance arm meansbeing supported upon a pivot point 102. A suitable weight in the form ofa brass block 104 is supported from the opposite end of the beam balancearm to serve as a counterbalance against the weight of the buffer bag.Giving due consideration to the weight of the beam balance arm itself,it will be appreciated that variations in the amount of fluid within thebuffer bag 64 will cause the beam balance arm to pivot, in one directionor the other, about the pivot point 102.

Three different sensing means are associated with the beam balance arm100 for causing various machine operations in response to differentbuffer bag weights. The first of these sensing mechanisms is amicroswitch 106 which acts as the buffer bag high limit switch and whichis actuated when the weight of the buffer bag plus the fluid containedtherein is approximately 280 grams. Actuating of the switch 106 stopsthe blood or input pump 62 and simultaneously initiates a needle rinsecycle. This needle rinse cycle continues until the next lowermicroswitch, designated 108 and generally called the refill bufferswitch, is actuated. As the fluid flows out of the buffer bag throughthe line 90 to the centrifuge 52, the weight of the buffer bag graduallydecreases, and when this weight drops to about 60 grams, the switch 108is actuated. Actuation of the switchl08 turns off the needle rinse cycleand starts the input or blood pump 62 and its coupled anti-coagulantpump 58. Since it takes about 12 seconds for the input pump 62 toaccelerate to its normal speed, and since the output pumps 66, 68 and 70are operating, there must be a sufficient quantity of fluid remaining inthe buffer bag to supply these output pumps so that the buffer bag willnot become completely depleted before the new anti-coagulated bloodsupply is furnished thereto. Actuation of the switch 108 also sounds anaudible chime device to indicate to the donor and the operator thatblood is again being pumped from the donor's body. Finally, the lowestof the switch devices is a microswitch generally designated 110, whichis called the buffer low switch. This switch is actuated when the levelof the fluid within the buffer bag 64 drops to such a degree that theweight of the bufier bag and fluid is only 30 grams. This conditioncould occur if the input or blood pump 62 is accelerating at too low arate for the flow rate of the output pumps. When the switch 110 isactuated, the same acts as a safety device to automatically stop theoutput pumps 66, 68 and 70 until the quantity of anti-coagulated bloodin the buffer bag has had a chance to build up to a proper level. Whenthis occurs, the output pumps are again started automatically. Actuationof the switch 110 will also cause a buuer to sound and a low limit lightto flash on and off, such flashing and buzzing continuing until a safefluid level is reached within the buffer bag. Switches 106, 108, and 110are shown in FIG. 1 as being operatively connected to AC pump 58 andblood pump 62 through connecting means 107 and 109.

To give a further understanding of the system as shown in FIG. I, itwill be seen that level sensing means 112 are associated with each ofthe IV or intravenous bottles. Specifically, these bottles are thepriming saline source 56, the anticoagulant source 60 and theintravenous saline drip source 82. Each of the sensing means 112 usesmicroswitches to perform two functions, namely, a warning function and astop function. The warning function serves to indicate that a particularIV bottle is running low and that a fresh bottle should be used toreplace the same. Since these bottles drain very slowly, there is ampletime for the operator to replace a partially empty bottle with a new orfresh bottle. The IV bottle warning signal will operate only when thebuffer bag beam balance arm is in a high limit condition since, at thistime, the buffer bag is full and the anti-coagulant pump 58 and bloodpump 62 are turned off. This condition will be sensed when the weight ofan IV bottle is milliliters, plus or minus 20 percent, and at this time,a buzzer will sound continuously until the low IV bottle is replaced bya new bottle. Also, a flashing light on the console will indicate thatthe IV bottle is low. However, in the event that the warning buzzer andthe IV bottle low light are ignored, then eventually one IV bottlesupply will become depleted, and when this occurs, the sensor 112 mustperform the stop function. This stop function is reached when thequantity of fluid remaining in an IV bottle is 60 milliliters, plus orminus 20 percent. At this minimum level, a further switch in the sensorunit 112 will transmit a signal to the buifer high limit switch 106,thereby stopping the anti-coagulant pump 58 and blood pump 62 andsimultaneously initiating a needle rinse cycle. The warning buzzer andIV bottle low light still continue to operate to indicate the conditionto the operator. If the operator should push the reset switch, this willmomentarily start the input pump 62 operating, but immediately uponrelease of such switch, this pump will again stop. In any event,operation of the reset switch does not silence the buzzer or stop theindicating light from flashing. It will be understood and appreciatedthat if this condition continues for any length of time, the quantity offluid in the buffer bag will gradually lower and the buffer bag beambalance arm will attempt to actuate the buffer refill switch 108.However, the sensor switch 112 will override this refill switch and willprevent the blood pump 62 from being started to refill thebuffer bag.Finally, the buffer bag will reach its low level at which time theswitch 110 will be operated to stop the output pumps. At this time, allof the machine pumps and hence all blood flow will be stopped but theaudible and visible signal means will continue to operate to indicatethe dangerous condition of the machine. Of course, the prime reason forarranging the system so that the IV stop function overrides the refillfunction, is to prevent the machine from operating if the supply ofanti-coagulant 60 becomes exhausted. The donors blood cannot be runthrough the machine without first being anti-coagulated since this wouldcreate a condition wherein the blood would readily clot.

To complete the description of the schematic diagram shown in FIG. 1, itwill be seen that a vacuum pump means 114 is coupled to the casing ofthe centrifuges 52 and 54. This vacuum pump means serves to drain anyfluid spill-over into the centrifuge casings.

Insofar as the output from the centrifuge 52 is concerned, it will beseen that the red cells pass through the line 92 and are returned to thedonor 50. The plasma passes through the needle rinse assembly 72 and iseither used to perform a needle rinse function, or alternatively, isrecombined with the red cells for a return to the donor. The white cellspumped from the centrifuge 52 go to a collection means generallydesignated 116.

Insofar as the second centrifuge 54 is concerned, it was previouslymentioned that this centrifuge could be used to further refine aparticular fraction of blood from the centrifuge 52. For instance, theplatelets may be removed from the centrifuge 52 along with the plasma inthe form of plateletrich plasma. If it was desired to separate theplatelets from the plasma, the same could be passed through the secondcentrifuge 54 with the platelets being supplied to a collection means118 and the plasma being returned to the line flowing to the needlerinse assembly. Alternatively, if the platelets were removed with thewhite cells, such a combination fraction could again be passed throughthe second stage centrifuge 54 to separate the platelets from the whitecells. Finally, it is possible to use the second stage centrifuge 54 toprocess other components. For example, it can be used to removecryogenic proteins previously precipitated by chilling the plasma as itpasses from the first stage centrifuge to the second stage centrifuge.

Finally, associated with the output tubing 86, there is an occluded veinsensor generally designated 120, which can be of any suitable type forsensing collapse of a vein. In the return line or tubing 92, there is abubble detector unit generally designated 122, and a return heatergenerally designated 124, each of which will also be described furtherhereinafter.

Considering now the more detailed aspects of the present invention,FIGS. 2, 3 and 4, respectively, illustrate top, front and rearelevational views of the in vivo blood separator machine, the same beinggenerally 150. A control console generally designated 152 is mounted onthe top or upper surface 154 of the machine, and the details of thisconsole will be described more fully hereinafter. The machine includes amain framework, generally designated 156, which is supported on wheelsor casters 158 to enable ready transport of the machine. A bottommounting plate extends across the bottom of the frame means 156 formounting some of the components of the machine 150, others of suchcomponents being supported by the upper or top surface 154 or by anintermediate supporting plate member 160. An examination of FIGS. 2, 3and 4 will show the general location of the centrifuge means 52, and 54,of the various pump means, of the waste divert assembly, and the needlerinse assembly, and of the various driving or operating means for eachof these portions of the machine. The details of such driving means willbe described further hereinafter.

To understand the specific nature of the centrifuge assembly 52,attention is directed to FIG. 5 wherein the details of the same areshown. The centrifuge includes a casing 162 mounted beneath an openingin the top 154 of the machine. Such casing includes an enlarged centralbottom hole or aperture 164 for receiving a driving plate 166 mounted ona shaft 168 of a l volt direct current shunt wound drive motor 170. Thecasing 162 also includes at least one drain hole 172 radially displacedfrom the central aperture 164, with the purpose of the drain hole beingto couple the interior of the casing 162 with the vacuum pump means 114.As such, the vacuum pump will serve to draw off any fluid spill-overinteriorly of the casing. A drive belt 174 extends between the motordrive shaft 168 and a motor tachometer generator unit 176. A motorcontrol unit senses any back EMF generated by the armature of thecentrifuge drive motor 170 and compares the same with the setting of themotor speed control potentiometer. Any speed variation of the drivemotor 170 caused by an increase or decrease in the load thereupon willcause a corresponding increase or decrease in back EMF which will besensed and corrected for by the control unit.

The centrifuge also includes a bowl or shell generally designated 178which is disposed within the casing 162. The shell 178 has an upstandingcylindrical side wall means 180 which terminates in an outwardlydirected flange 182. The bottom wall 184 of the shell is provided withan alternating rib and groove assembly 186, which cooperates with asimilar assembly 188 on the driving plate 166. In this manner, operationof the drive motor 170 will impart a rotation to the driving plate 166,and this rotation will in turn be imparted to the centrifuge shell 178to rotate the same. Rotational speeds of the centrifuge range from 0 to2,500 rpm plus or minus 10 percent. Rotational speeds within this rangewill cause gravitational forces from O to 560 G, plus or minus 20percent, at the outermost separation surfaces.

The interior of the side walls 180 of the centrifuge shell 178 serve toprovide the outer boundary for the separation channel. Starting at thetop of the centrifuge shell, a wall portion 190 extends linearlydownwardly for a predetermined distance, then merges smoothly into aninwardly and downwardly inclined wall portion 192 which in turn mergesinto another linearly extending wall portion 194. This wall portion 194extends downwardly until the same intersects the inner surface 196 ofthe bottom wall 184.

Another portion of the centrifuge assembly 52 is the center or fillerpiece generally designated 200. This filler piece is suitably suspendedfrom the top cover of the centrifuge assembly, in a manner which will bedescribed hereinafter. A central bore 202 extends completely from theupper surface of the filler piece to the bottom surface 204 thereof.This bore 202 provides the input channel to the centrifuge. The fillerpiece itself is cylindrically shaped and of a somewhat smaller diameterthan that of the shell wall portion 194. As such, the outer or side wall206 of the filler piece is spaced slightly away from the wall portion194 to thereby provide the other boundary of the separation channel.This channel itself is designated 208 and extends with uniform thicknesssubstantially for the height of the shell wall portion 194.Substantially opposite to the inclined portion 192 of the centrifugeshell, the side wall 206 of the filler piece is radially curved, asshown at 210. This curve merges into an inwardly extending shoulderportion 212 which again turns into an upwardly extending portion at 214to blend into the top surface 216.

By referring to FIG. 6, as well as FIG. 5, it will be seen that acentral recess is provided in the top wall 216 of the filler piece 200,and an O-ring 218 of substantially rectangular cross-sectionalconfiguration is disposed within a groove about the periphery of thisrecess portion. Four equally spaced tapped holes 220 are provided in theupper surface 216 of the filler piece for the purpose of receivingscrews which couple the tiller piece to the top cover of the centrifugeassembly. O-rings 222 having a rectangular cross-sectional configurationsimilar to that of the O-ring 218 are seated within grooves surroundingeach of these tapped holes 220. Radially extending channels or passages224 are provided at intervals along the top surface 216 of the fillerpiece, with each of these channels extending between the wall surface214 and the side wall surface of the O-ring 218. These grooves orchannels 224 serve as plasma ports as will be described more fullyhereinafter.

Referring back to FIG. 5, it will be seen that the centrifuge assemblyalso includes a top cover means generally designated 226, such covermeans being fabricated of a clear polycarbonate plastic material whichpermits visual observation of the separation occurring within thecentrifuge. The top cover includes a flange portion 228 which abutsagainst the top of the flange portion 182 of the centrifuge shell. Asealing O-ring 230 is interposed between the two flange portions toprevent any leakage. Also, aligned apertures are formed through theflanges 182 and 228 to permit reception of a nut and bolt fasteningmeans 232 which couples the cover to the shell. A short vertical wallportion 234 extends downwardly from the top cover to mate contiguouslywith the wall portion 190 of the centrifuge shell, thereby properlypositioning the cover on the shell. At the end of the vertical wallportion 234, there is a horizontal or radially inwardly stepped portion236 which merges with the top of another short vertical wall portion238. At the bottom of the wall portion 238, there is another radiallyinwardly stepped portion 240 which merges with the top of a furthervertical wall portion 242. The bottom of this vertical wall portion 242merges with the bottom surface 244 of the top cover. This surface 244rests upon the top surface 216 of the filler piece 200. A small centralboss 246 depends beneath the bottom wall 244 to rest in the recessformed in the central top of the tiller piece.

Four holes 248 are formed through the top cover means 226, with suchholes being spaced 90 degrees from one another. Thus, these holes 248align with the holes 220 formed in the top of the filler piece. Screws250 extend through the holes 248 and into the holes 220 to therebysecurely attach the filler piece to the cover. As can be seen from FIG.5, when the filler piece is attached in this manner, the bottom surface204 thereof is spaced slightly away from the bottom inner surface 196 ofthe centrifuge shell. Hence, a small space is provided so that the wholeblood flowing into the centrifuge through the bore 202 can spreadoutwardly to the separation channel 208 and can then climb upwardlytherealong as the centrifuge is operated.

A seal means generally designated 252 forms the upper part of thecentrifuge means 52, as can be seen in FIG. 5. Such seal means includesa lower rotating seal means generally designated 254 and an upperstationary seal means generally designated 256. The lower or rotatingseal means 254 fits within a first stepped recess 258 on the top of thetop cover means 226. A second stepped recess 260 is also provided in thetop cover means, with the stepped portion 260 being somewhat smallerthan the stepped portion 258. A central bore 262 extends completelythrough the top cover means at the center thereof, with such boreextending from the stepped portion 260 to the bottom projection 246. Ascan be seen, the bore 262 in the top cover is coaxial with the centralbore 202 of the filler piece 200.

The stepped portion 260 in the top cover contains a plurality of spacedgrooves concentrically arranged about the central bore 262 thereof. AnO-ring having a rectangular cross-sectional configuration is mountedwithin each of these grooves. All of such O-rings can be designated 264,but it will be appreciated that the size or diameter of such O-ringscontinuously increases. Since the bottom of the lower seal means 254abuts against the top of the various O-rings 264, the overall effect ofsuch an arrangement is to set off a series of channels or annular spacesbetween the stepped portions 260 and the bottom of the seal means 254.The smaller or innermost O-ring 264 defines therewithin a circularopening designated 266, with such opening being axially aligned with thecentral bore 262. Between this innermost O-ring and the next adjacent O-ring, a first annular channel 268 is formed. Between the second O-ringand the next adjacent O-ring, a second annular channel 270 is formed.Finally, between said next adjacent O- ring and the outermost O-ring, athird or outer annular channel 272 is formed. Each of the annularchannels 268, 270 and 272 serves to receive a separate fraction of theblood separated in the centrifuge means 52.

To more fully understand the nature of the separation or fractionationwhich occurs within the centrifuge means 52, it can be seen from FIG. 5that the separation channel 208 having an optimum radial dimension of lmillimeter, extends upwardly with uniform thickness until it reaches theinclined wall portion 192 of the centrifugal shell. At this point, theseparation channel 208 merges into an enlarged separation space'orchamber 274. When whole blood enters the centrifuge means 52, it travelsdownwardly through the central bore 202, then outwardly in the spacebetween the bottom 204 of the filler piece and the bottom surface 196 ofthe shell. Then, such outwardly extending whole blood turns upwardly andclimbs through the separation channel 208 to enter the space 274. Suchclimbing action is created by the centrifugal force generated byrotation of the centrifuge shell, filler piece and top cover. Due tothis centrifugal force, the whole blood in the space 274 starts toseparate due to differences in specific gravities of the variousfractions thereof. The red cells are the heaviest of the fractions, andthese are thus outermost within the space 274. The white cells are thenext heaviest and these are thus positioned adjacent the red cells, andthe plasma is the lightest and hence is disposed furthest inwardlywithin the centrifuge. For purposes of illustration, blood is shown inthe space 274 of the centrifuge assembly in FIG. 5, with the red cellsbeing designated R, the white cells being designated W, and the plasmabeing designated P. As was previously mentioned, the quantity of whitecells in the blood is extremely small, and accordingly, as separationinitially starts, there is merely an interface line between the plasma Pand the red cells R. As was also previously mentioned, proper regulationof the output pumps can adjust the position of this plasma-red cellinterface line to space the same closer to the shell wall H or furtheraway therefrom. However, after the blood has been separating for awhile, the white cells W start to build up within the centrifuge to forma buffy coat of the shape generally illustrated in FIG. 5. It will beseen that the white cell layer effectively floats on the red cells andplasma. Then, each of these individual fractions is transferred to itsown particular annular channel in the top cover.

To transfer the red cells, a red cell port 276 extends from the wallportion 238 of the cover to the first annular channel 268. Hence, as thered cell output pump 66 is operated, providing a pull through the sealmeans 252 in a manner to be presently described, the red cells from thelayer R are drawn through the port 276 and into the annular channel 268.The white cell port 278 extends from the portion 242 of the top cover tothe annular channel 270. Thus, as the white cell output pump 68 isoperated through the seal means 252, the white cells W are drawn throughthe port 278 to the annular channel 270. Finally, as was previouslymentioned, the plasma port 224 extends through the top surface 216 ofthe filler piece 200. These ports communicate with bores 280 which inturn communicate with the annular channel 272. Thus, as the plasmaoutput pump 70 is operated through the seal means 252, the plasma P isdrawn through the ports 224, and the bores 280 to enter the outermostannular channel 272.

To now understand the nature and construction of the seal means 252,attention is directed to FIGS. 7 through ll which show the individualseal means 254 and 256 in detail. The rotating seal means 254 is formedof a synthetic resin and includes a circular base portion 300 having aflat bottom surface 302. The size of the base portion 300 correspondssubstantially to the size of the stepped portion 258 in the top cover226 and when the rotating seal 254 is positioned within the top cover,the bottom surface 302 thereof abuts against the top of the O-rings 264.To prevent rotation of the seal means 254 relatively to the top cover226, a small notch 304 is provided in the periphery of the base 300.This notch 304 mates with a guide pin 306 positioned at one edge of thestepped recess 258 in the top cover. The seal means 254 also includes anupstanding cylindrical body portion 308 integral with the base portion300, but having a cross-sectional diameter somewhat smaller than that ofthe base 300. The top surface 310 of the portion 308 is divided into aseries of concentrically arranged grooves and channels. At the center ofthe piece, a central bore goes straight through the seal means 254.Then, annular channels are concentrically arranged about the centralbore 322, with such channels, in order of increasing diameter, beingdesignated 314, 316, 318 and 320. The central bore 322 extends from thetop surface 310 to the recess or opening 266,

and when the seal piece 254 is properly positioned in the top cover, thebore 322 is coaxial with the bores 262 and 202. The channel 314 is ofsubstantially the same diameter as the previously described red cellchannel 268 and eight small bores 324 communicate therebetween, therebyassuring that the red cells can be transferred from the channel 268 tothe channel 314. The channel 316 is of substantially the same diameteras the white cell channel 270 and communicates therewith through fourequally spaced bores 326. Thus, the white cells from the channel 270 canbe transferred through the bores 326 to the channel 316. The channel 318is of substantially the same diameter as the previously described plasmachannel 272 and communicates therewith through four spaced bores 328.Hence, the plasma can be transferred from the channel 272 through thebores 328 to the channel 318. The outermost channel 320 has no boresextending therefrom through the means 254, and instead, in a manner tobe presently described, this outer channel 320 is filled with a salinesolution to act as a barrier between air and the nearest internal bloodpassage.

As will be seen, there is a series of small annular lands which act asboundaries separating each of the channels 314, 316, 318 and 320. Eachof these lands has a flat top defined by the top surface 310 of the sealmeans 254.

By referring to FIGS. 9-11, the exact nature of the upper or stationaryseal means 256 can be understood. This seal means is fabricated ofstainless steel and is essentially formed as a flat disc 340 having aflat lower surface 342 which is lapped to a flatness of three lightwaves or less, and a spaced parallel flat upper surface 344. The lowersurface 342 rests upon the upper surface 310 of the seal means 254,which upper surface is also lapped to a flatness of three light waves orless. Concentrically arranged annular channels 348, 350, 352 and 354 aredesigned to mate respectively with the annular channels 314, 316, 318and 320, of the seal piece 254. Hence, the channel 348 in cooperationwith the channel 314 serves to define the red cell annulus. Similarly,the annular channel 350 in cooperation with the annular channel 316serves to define the white cell annulus. Similarly, the annular channel352 in cooperation with the annular channel 318, serves to define theplasma annulus. Finally, the annular channel 354 in cooperation with theannular channel 320, serves to define the saline seal annulus. A centralbore 356 extends through the member 340 with such bore being coaxialwith the bore 322 in the companion seal means. A bore 360 extendsthrough the member 340 from the annular channel 350 to allow the whitecells to be pumped out. A bore 362 extends through the member 340 fromthe annular channel 352 to allow the plasma to be pumped out. A bore 364extends through the member 340 from the annular channel 354 to allowsaline to be pumped in.

Each of the various bores extending through the member 340 terminates atthe upper surface 344 in communication with small tube means generallydesignated 372. These tubes, in turn, are coupled with the tubingharness to receive the plastic tubing from the machine.

In use, with the stationary seal means 256 juxtaposed to the rotatingseal means 254, saline is pumped inwardly through the port 364. In theoutermost annulus, this saline acts as a seal to prevent any air fromworking its way inwardly and also acts as a barrier between air and thenearest blood passage. A pair of small holes 374 are provided onopposite sides of the top surface 344 of the stationary seal means 256.The purpose of these holes 374 is to receive guide pins which maintainthe seal piece in a stationary, non-rotating manner, while at the sametime, applying adequate downward pressure thereto. By referring back toFIGS. 2 and 3, it will be seen that an arm means 380 overlies each ofthe centrifuge means 52 and 54. The outermost end of the arm means ispivotally mounted at 382 to permit the arm 380 to be raised and lowered.Two small guide pins 384 depend from the inner end of the arm 380 wherethe same overlies the centrifuge means, with these pins 384 fitting intothe holes 374 in the stationary seal means 256. A screw knob 386 isremovably threaded upon a stud, not shown, which extends upwardly fromthe top 154 of the machine and through a slot in each arm 380. Thus,when the threaded knob 386 is removed, the arm 380 can be swung upwardlyto permit the centrifuge assembly to be removed from or introduced intoits casing 162. Once the entire centrifuge assembly has been properlypositioned within its casing, the arm 380 is swung downwardly and thepositioning pins 384 are located in the guide holes 374 therebymaintaining the seal piece in a stationary, non-rotating manner. Then,the threaded knob 386 is applied to its mounting stud and is tighteneddown, thereby causing the arm to apply a pressure against the sealmeans, such pressure being effective to maintain proper contact at theseal means 252.

With the foregoing explanation in mind, it might be well to summarizethe operation of the centrifuge means 52. Assuming that all of the partsare properly positioned, as shown in FIG. 5, and further assuming thatthe machine tubing harness is coupled to the tubes 372, and that the arm380 is properly tightened down, the drive motor 170 can be set intooperation to cause a rotation of the centrifuge, and the whole blood canthen be introduced thereinto from the buffer bag. Such whole bloodenters through the central bore 356 in the stationary seal means,traverses the aligned central bore 322 in the rotating seal means, thentraverses the central bore 262 in the top cover, and finally traversesthe central bore 202 in the filler piece. The whole blood then spreadsout along the bottom of the centrifuge and climbs along the wallsthereof through the separation channel 208, finally entering the space274. As separation is occurring within the centrifuge, saline is beingpumped into the grooves and the outermost channel of the seal means.Operation of the red cell pump 66 will cause the red cells R from thespace 274 to be withdrawn through the port 276, into the channel 268,through the bores 324, into the annular channels 314 and 348, throughthe outlet port 358 and its associated tubing and eventually through thepump. Similarly, operation of the white cell pump 68 will cause thewhite cells W from the space 274 in the centrifuge to be withdrawnthrough the white cell port 278, into the annular channel 270, thenthrough the bores 326 in the rotating seal, into the annular channels316 and 350 between the seals, then through the outlet port 360 in thestationary seal, through its associated tube 372, and finally throughthe white cell pump itself. Finally, operation of the plasma pump 70will cause the plasma P from the space 274 to be withdrawn through theplasma ports 224, then through the bores 280 in the top cover and intothe annular channel 272, thereafter traveling through the ports 328 inthe lower or rotating seal into the annular channels 318 and 352 betweenthe seals, then through the outlet port 362 in the stationary seal,through its associated tube 372 and finally through the plasma pumpitself. Variations in the speed at which the pumps 66, 68 and 70 aredriven will naturally vary the rates at which the separate fractions arewithdrawn from the centrifuge.

Considering now the various pumps utilized in the machine 150, attentionis directed to FIGS. 12 and 13, wherein a typical pump is illustrated.All of the five pumps in the machine are of the peristaltic type havinga rotating portion which progressively occludes the plastic tubingpassing through the pump. The input or blood pump 62 is illustrated inFIG. 12 merely as a typical pump construction. All of the other pumpsexcept the white cell pump 68 are similar to the pump shown in FIG. 12.The pump includes an upstanding outer casing or sleeve designated 400,such sleeve having a circular inner race 402. An inlet opening 404 andan outlet opening 406 are spaced apart along the sleeve 400 to permitthe plastic tubing carrying the blood or other fluid to be pumped to beinserted within the pump. Insertion of such tubing within the pump isfacilitated by the construction of the pump cap generally designated408, and as can best be seen in FIG. 11. This pump cap 408 includes aflange having a small groove 410 therein and the tubing to be introducedinto the pump is placed within such groove 410. Then, as the cap 408 isrotated, either automatically or manually, the tubing is effectivelythreaded into the interior of the pump to follow the contour of the race402, except for that small portion thereof between the openings 404 and406.

The pump is operated by a pump motor and drive means of a type to bepresently described, and operation of such motor and drive means servesto rotate a driving disc 412 located within the sleeve 400, as can beseen in FIGS. 12 and 13. A pair of rollers 414 are rotatably mounted onthe top of such disc 412, with the rollers being spaced 180 degreesapart. The periphery of the rollers 414 extends slightly beyond the edgeof the driving disc 412 but is spaced away from the inner race 402 ofthe pump by a distance substantially equal to twice the wall thicknessof the tubing to be passed through the pump. Thus, as the driving disc412 rotates, it causes a simultaneous rotation of the rollers 414, withthese rollers serving to collapse or occlude the plastic tubing betweenthe outer periphery of the rollers and the sleeve race 402. Theprogressive rotation of the rollers 414 serves to progressively occludethe tubing, thereby conveying or advancing any fluid containedtherewithin.

In order to properly position the tubing within the pump housing orsleeve 400, tubing guide means are provided. Such guide means includes aflat plastic butterfly disc 416 which rests upon the driving plate 412and extends therebeyond substantially to the inner race 402. A top oroverlying butterfly plate 418 is provided with a peripheral notch 420,as shown in FIG. 13, within which the tubing, designated T in FIG. 13,can be positioned. A pair of spaced holes 422 extend through the guidepieces 416, 418 and terminate in aligned threaded holes in the drivingplate 412. Similarly, spaced holes are provided in the cap 408 and thusthrough the use of a pair of elongated screws, the cap 408 and thetubing guide means 416 and 418 can be coupled to the driving plate 412for simultaneous rotation therewith.

To understand the manner in which the various pumps of the presentinvention are driven, attention is directed to FIGS. 14 and 15 hereof.The driving motors for the pumps of the present invention are 110 voltdirect current shunt wound gear head motors. Each of the output pumps66, 68 and 70 is driven by its own individual motor, and the drive meansfor these output pumps is shown in FIG. 14. On the other hand, a singlemotor drives both the anti-coagulant pump 58 and the whole blood inputpump 62, and this driving arrangement is shown in FIG. 15.

Referring to FIG. 14, the output pump drive arrangement includes anelectric driving motor 430 having an outboard shaft 432 at one endthereof and a coupled gear head or gear drive arrangement 434 at theopposite end thereof. The gear head, when operated by the drive motor430, serves to rotate an upstanding shaft 436 which in turn, mounts adrive pulley 438. The drive pulley 438 operates a driving belt 440 whichis coupled to another pulley 442 on the depending shaft 444 of anelectric clutch mechanism 446. When the machine power is on, theelectric clutch 446 is energized to prevent the pumps from beingmanually operated. The electric clutch mechanism 446, in turn, iscoupled by a shaft coupling means 448, to the driving disc 412 of any ofthe output pumps. For purposes of illustration, the plasma pump 70 hasbeen illustrated in FIG. 14.

At the forward end of the drive motor 430, an elongated bracket 450 isprovided, such bracket serving to support a tachgenerator 452 having aforwardly extending shaft 454. A first drive pulley 456 is mounted onthe motor shaft 432 and a superposed pulley 458 is mounted on thetachgenerator shaft 454. A driving belt 460 extends between thesepulleys whereupon operation of the drive motor 430 causes a simultaneousoperation of the tachgenerator 452. For the red cell and plasma pumps,the bracket 450 is in upstanding relationship, as shown in FIG. 14.However, for the white cell pump, the bracket 450 depends downwardly andthe tachgenerator 452 'is mounted beneath the drive motor 430, as shownin FIG. 3.

The various tachgenerators 452 are utilized to convert the rpm of thedrive motor 430 into a related output on the unit console 152. Eachtachgenerator 452 is a permanent magnet generator which delivers 3.8volts for each revolutions per minute of the drive motor 430. The outputof each individual tachgenerator is fed to a meter calibration circuitwhich consists of a voltage dropping resistor and a calibrationpotentiometer to match the output of the tachgenerator at a given speedto the dial calibration of an individual meter on the console 152.

Referring now to FIG. 15, which shows the drive arrangement for theanti-coagulant pump 58 and the blood pump 62, it will be seen that thedrive motor, its attached gear head, the bracket and the tachgeneratorare all identical to that just described in connection with FIG. 14.However, on the gear drive shaft 436, an enlarged driving pulley 470 isprovided, and on the depending shaft 444 from the clutch mechanism 446for the whole blood pump 62, a small upper pulley 472 and a small lowerpulley 474 are provided. A driving belt 476 couples the pulley 470 withthe uppermost pulley 472. Another driving belt 478 extends from thelowermost pulley 474 to an enlarged idler pulley 480. The idler pulley480 carries a connected smaller pulley 482 which is connected by adriving belt 484 to an enlarged pulley 486 on the shaft 444 from theclutch mechanism for the anti-coagulant pump 58. The purpose of thistype of drive arrangement becomes apparent when it is remembered thatthe driving motor shown in FIG. 15 operates both the whole blood pump 62and the anticoagulant pump 58, but that the anti-coagulant pump is tooperate at only a fraction of the speed of the whole blood pump. Whenusing the anti-coagulant solution commonly used in the machine, namelyACD, an acid-citrate-dextrose solution, the ratio of the whole blood toanti-coagulant is 7:1. This 7:1 reduction in the speed of the blood pumpis accomplished through the use of the idler pulley 480 which reducesthe speed of the blood pump shaft by a factor of 7. This reduced speedis then transmitted to the anti-coagulant pump shaft.

All of the driving mechanisms for the pumps is located on the mountingplate 160 within the machine, as can best be seen from FIGS. 3 and 4. Tocomplete the description of the various pumps and their driving means,the motor 430 driving the blood pump 62 also drives a cam which strikesa microswitch for every 0.7 revolutions of the input pump. Thisgenerates an impulse which initiates an advance in the total milliliterinput counter on the console 152. Each count on the counter representsan inflow of l milliliter. An acceleration control device to bedescribed presently controls the operation of the whole blood pump 62.This pump always starts at 0 revolutions per minute and gradually buildsup to a preselected speed. The speed of the input pump varies between 0and 255 milliliters per minute, plus or minus 10 percent. The red cell,plasma and white cell pumps all operate between 0 and 100 millilitersper minute, plus or minus 10 percent. The plastic tubing utilized in allof the pumps has a basic size of 0.25 inches outside diameter and 0.125inches inside diameter. However, provision is made to substitute variousdiameters of rollers 414 to permit the optional use of tubing of variousdiameters and wall thicknesses.

As was previously described, the needle rinse assembly 72 includes apair of valves 74 and 76. Similarly, the waste divert assembly includesa pair of valves 94 and 96. For an understanding of the construction ofsuch valves, attention is directed to FIG. 16 wherein a typical valve isillustrated. All of the valves used in the machine are of the solenoidtype, that is, electrically operated valves including a solenoid coredesignated 500; The core carries a projection 502 having an apertureextending centrally therethrough, through which the solenoid core orplunger 504 passes. A head 506 is provided on the end of the solenoidplunger and as the plunger is drawn into the core, the bottom of thehead 506 abuts against the top of the projection 502. The projection 502includes an elongated slot 508 communicating with the bore through whichthe plunger S04 passes. A first pin 510 is attached to. the projection502 at one end of the slot 508. A second pin 512 is attached to theplunger 504 and extends through the slot 508 in parallel relation withthe fixed pin 510. The plastic tubing utilized in the machine 150 passesbetween the pins 510 and 512, and when the valve is in closed position,as shown in solid lines in FIG. 16, the pins 510 and 512 serve to pinchclosed the tubing passing therebetween, thereby preventing flow throughsuch tubing. On the other hand, when the valve is moved to openedposition, as shown in dotted lines in FIG. 16, the movable pin 512 ismoved to the opposite end of the slot 508 and the tubing is thereforenot collapsed or pinched. Accordingly, flow through such tubing can beaccomplished.

In practice, one of the valves of each assembly is normally opened whilethe other valve thereof is normally closed. For example, in the needlerinse assembly 72, the valve 74 is normally closed and the valve 76 isnormally opened. Similarly, in the waste divert assembly 78, the valve94 is normally opened and the valve 96 is normally closed. However, whenthe machine goes into a needle rinse cycle, the positions of the valvesin the assembly 72 are reversed, and at that time, the valve 74 isopened and the valve 76 is closed. Similarly, if the machine goes into awaste divert cycle, the valve 96 is opened and the valve 94 is closed.

Continuing with the description of the machine 150, attention isdirected to FIG. 3, wherein the vacuum pump means 114 can be seenmounted on the bottom of the machine frame 156. Two vacuum pumps areprovided, with one being attached to the centrifuge casing bore 172 ofthe centrifuge means 52, and the other being attached to the same casingbore for the centrifuge means 54. Each vacuum pump consists of ahysteresis disc motor 540 which drives a miniature suction pump 542.These motors are under control of the main machine power switch and thusrun continuously as soon as the power to the machine is turned on.

Also mounted on the bottom of the machine frame 156, as

, can be seen in FIGS. 3 and 4, is an acceleration control devicegenerally designated 546. This device is intended to control theacceleration of the input or blood pump 62. The acceleration controldevice 546 includes a 4 rpm two-phase synchronous reversible motor 548,a powerstat unit 550, an associated power transfer relay and associatedlimit switches. The powerstat is mechanically connected to the motor andcontrols the amount of 1 15 volt AC power being supplied to the inputpump variable control on the control panel or console 152. When thebuffer bag drains to a point where the refill buffer switch 108 isactuated, a signal will be transmitted to the motor 548 thereby causingthe same to drive the powerstat in a forward direction which increasesthe voltage to the input pump variable control. The length of timeneeded to increase the powerstat 550 from to 115 volts AC, as applied tothe variable control means on the console 152, is about 12 seconds. Atthe expiration of this 12 second time, the power transfer relay of thedevice 546 transfers the full 115 volts AC to the control panel inputpump variable control.

As was also mentioned, the acceleration control device 546 includes aforward and a rearward limit switch actuatable by the motor 548. Whenthe motor actuates the forward limit switch, the direction of driving isreversed and thus, the motor returns the powerstat 550 to a 0 voltoutput to be ready to start the next cycle for drawing blood from thepatient. This reverse driving of the powerstat will end when the motoractuates the reverse limit switch. Thus, while it will be appreciatedthat the maximum speed of the input or blood pump 62 is controlled bythe variable pump control on the control panel or console 152, the timeperiod required for the blood pump 62 to reach this preselected speed isgoverned by the acceleration control device 546. In other words,regardless of .the setting on the console, it will require about 12seconds for the pump to accelerate to its preset speed. This type ofcontrol is important to prevent the occurrence of a vein occlusion whichmight otherwise occur if the pump instantaneously went into operationand withdrew a high flow rate from the donors vein, and also isimportant to prevent any hemolysis or trauma damage to the red cells.

Referring again to the inflatable cuff 84, the same need not beillustrated in detail herein since it merely corresponds to theconventional form of inflatable arm cuff, such as is commonly used inconnection with sphygmomaneters. However, instead of being manuallyinflated and deflated, as is the conventional arm cuff, the arm cuff 84of the present invention is actuated by a cuff pump assembly generallydesignated 554 and carried on the bottom of the machine frame 156, asshown in FIG. 4. The cuff pump assembly 554 includes a solenoid pinchvalve means 556, of the type previously described, a pressure switch 558and a combined pump and motor 560. The cuff pump automatically inflatesthe arm cuff 84 around the patients donating arm to a pressure between40 to 60 millimeters of mercury. The solenoid valve 556 is normallyopened, however, when the buffer bag drains to a point where the refillbuffer switch 108 is actuated, then the valve 556 will close on an airexhaust tube leading from the motor and pump 560. This will cause themotor to operate a piston within a pressure chamber, thereby acting as apump to provide pressurized air to the arm cuff 84. This air will beginto inflate the arm cuff and will continue to do so until the pressureswitch 558 senses the preselected pressure of between 40 to 60millimeters of mercury. At such time, the switch 558 cuts off power tothe motor, but if the pressure at the cuff drops below the preselectedrange, the pressure switch 558 will again start the motor 560 tomaintain proper pressure at the cuff. The cuff will remain inflateduntil the buffer bag is filled, thereby reaching its high limit andactuating the switch 106. When this switch is actuated, the valve 556 isde-energized, thereby opening the same to allow any pressurized air fromthe motor to vent off or exhaust. Simultaneously, power to the motor 560is interrupted. Except as described herein, the arm cuff is not normallyinflated and therefore, arm cuff inflation is only intermittent forperiods of time sufficient to refill the buffer bag 64. Provision ismade for manual inflation of the cuff during preparation of the machinefor use. The purpose of only intermittently inflating the cuff 84 whenthe donor is attached, is to provide the maximum degree of comfort forthe donor 50.

The power supply for the machine 150 is carried at the bottom of theframe 156 and is generally designated 564. Such power supply includes a48 volt DC power supply generally designated 566 and a 110 volt DC powersupply generally designated 568. The 48 volt power supply 566 is aferro-resonant transformer supply which is utilized to supply power toall of the relays, signal lights, sensing units and chime on themachine. Taps are provided on the secondary side of the powertransformer to allow the output voltage to be adjusted to a nominal 48volts. The 110 volt power supply 568 is used to supply power to the pumpmotor fields, the solenoid valves and the electric firction clutchmechanisms. This power supply is unregulated and line voltage variationswill cause proportional variations in the output voltage. Therefore, thepower supply 568 includes a variable auto-transformer, which permitsadjustment to the output voltage of 110 volts so long as the linevoltage is within plus or minus 10 percent of l 15 volts AC. The powersupply 568 also includes a meter for reading the value of the powersupply output voltage.

Referring again to FIGS. 3 and 4, there is shown therein at one end ofthe machine frame 156, beneath the console 152, a relay gate meansgenerally designated 580. This relay gate means includes 28 separate 48volt DC dual relays for accom plishing logic control function. Also, itincludes one 48 volt DC power transfer relay which is utilized inconnection with the acceleration control unit 546. Additionally, therelay gate includes a fuse panel 582 having six fuses 584 mountedtherein to assure electrical safety of the machine circuit. Finally, therelay gate means 580 includes a pair of volt AC timing motor assembliesgenerally designated 586, such assemblies providing timing pulses forthe indicating lights, the buzzer and the auxiliary needle rinse cycle.Each of the timing units 586 includes a small synchronous timing motorwhich drives a circuit breaker unit for timing pulses and a cam segmentto provide a longer time interval than is provided by the circuitbreaker unit. The timing motors are under the control of the main powerswitch drive 590 of the machine, such switch being mounted on the frontof the machine at the upper right hand corner thereof, just beneath theconsole 152. When the main power switch 590 is turned on, the timingmotors 586 are energized and will thereafter run continuously so long asthe machine is turned on. One of the timing units provides 48 volt DCpulses to pulse all of the indicating lights except the power on lightand the run light, and further serves to supply a timing pulse to soundthe buzzer for a period of about 3 seconds when an occluded vein issensed. This is the only time when the buzzer will be sounded for apreselected interval of time, and in all other circumstances, when themachine reaches a condition where the buzzer is actuated, the same willremain on until the condition is corrected. The other timing unit 586 isused to control the needle rinse cycle at the beginning of operation ofthe machine when the priming solution is being utilized to accomplishthe needle rinse rather than the patients own citrated plasma. Thistiming unit supplies a timing pulse of about 3 seconds when the primingfluid is supplied to the needle rinse, thereby creating a fast rinse.After such 3 second period, the needle rinse cycle is stopped. It will,however, be understood that this timing cycle is not utilized when thepatients own citrated plasma is being utilized for the needle rinseoperation.

' The machine also includes a control box generally designated 592, suchcontrol box being located along the bottom of the machine frame 156. Thecontrol box 592 includes a series of calibration potentiometers, abuzzer device and a chime device. The buzzer is intended to operate as awarning device to call the attention of the machine operator to the factthat an unsafe condition has been sensed. Thus, the buzzer will operatewhen an occluded vein is sensed, at an IV bottle warn or stoppedcondition, at the buffer low limit condition when the switch 110 isoperated, and at a bubble detect condition. Under all of theseconditions, except the occluded vein, the buzzer will operatecontinuously until the operator has taken appropriate corrective action.As just described, in the case of an occluded vein, the timing unit 586controls the buzzer to sound the same for a period of about threeseconds.

The chime is a two-tone device which is energized when the buffer refillcycle is reached. The purpose of the chime is merely to indicate to thedonor 50 that the buffer bag needs refilling and that the arm cuff isgoing to inflate and that the input pump will start to draw blood fromthe donors vein.

Finally, the control box 592 includes a series of calibrationpotentiometers which can be adjusted by means of a screw driver. Acalibration potentiometer is provided for each of the centrifugeassemblies 52 and 54, each of such potentiometers being a 50K, two wattcurrent limiting device used to calibrate the centrifuge meters on theconsole 152. Similarly, a calibration potentiometer is provided forcalibrating the white cell flow meter and for calibrating the returnflow rate meter. However, in the case of the calibration potentiometerfor the return flow rate meter, the driving source is a seriesarrangement of the red cell and plasma tachgenerators 452.

The details of the bubble detector 122 can be seen from FIG. 17 toinclude an inverted drip chamber receptacle 600 which is supported by anassembly 601 having a pivotally mounted arm 602 upon which thereceptacle is hung. A fitting 604 is provided at the bottom of thereceptacle 600 for receiving the return tubing 92. The receptacle 600 isnormally completely filled with whole blood which communicates with theblood flowing through the return tubing 92. However, if an air bubblecomes through the tubing 92, it rises into the receptacle 600 todisplace a portion of the blood therein. As this portion of blood isdisplaced from the receptacle, the weight of the receptacle is lessened.When eventually a sufficient volume of blood has been displaced from thereceptacle, such volume being approximately 8 grams, the weight of thereceptacle will be lightened to such a degree that the am 602 willactuate a sensing switch 606, thereby initiating a bubble detectcondition. Specifically, closure of the switch 606 sounds the warningbuzzer, causes an on and off flashing of the bubble detect light on theconsole and stops the centrifuge output pumps 66, 68 and 70.

To correct a bubble detect condition, the receptacle 600 must be removedfrom the arm 602 and turned upside down, thus causing the air to risetoward the fitting 604. Then, a clamp 608 on an air bleed tube 610 isopened to permit the collected air to bleed off from the receptacle 600through the tube 610. The receptacle 600 is thus refilled completelywith blood after which it is once again inverted and attached to the arm602. Since the weight of the filled receptacle is once again normal, theclamp 602 will move downwardly, thereby releasing the sensing switch606. The warning indicia and the output pumps can then again be resetfor nonnal operation.

As previously mentioned, a return heater 124 is provided along thereturn tubing 92, adjacent the bubble detector 122. The return heater isformed by a tank of heated water which is kept in circulation by acirculating pump. The return tubing 92 is formed into a coil portionwithin this tank to increase the distance and length of time requiredfor blood flowing through the tubing to traverse the tank. The heat fromthe water in the tank is transferred through the tubing 92 to raise thetemperature of the blood therewithin back to normal body temperature.

Referring again to FIG. 4, the back panel of the machine 150 will bedescribed. Such back panel is designated 620 and includes a left wasteconnector 622 and a left vacuum connector 624. The left waste connector622 is attached by tubing to the waste collect means associated with theleft centrifuge means 54-. An external tube can be attached to thisconnector to lead to a waste collection receptacle. The left vacuumconnector 624 is attached by tubing to the vacuum pump 542 associatedwith the centrifuge means 54 and again external tubing should beattached to this connector to permit the waste from the centrifugecasing to be drained to a waste receptacle. In a similar manner, a rightwaste connector 626 and a right vacuum connector 628 are provided tocooperate with the right centrifuge means 52.

The back panel 620 also includes a three prong female electricalconnector 630 for connection of the bubble detector sensor cable.Finally, the back panel includes three four prong female electricalconnectors 632, 634 and 636 provided for connection of the IV bottlesensor cables for the sensing mechanism 112. These three connectors areinternally wired in parallel. Thus, the connector 632 is provided forthe priming saline source 56, the connector 634 for the anti-coagulantsource 60 and the connector 636 for the intravenous saline source 682. Atwo-receptacle output 638 is also provided on the back panel 620 topermit attachment of devices such as an electrocardiogram where it isimportant for patients safety that the electrical ground be the same asthat of the machine itself.

Having now described the various components of the machine, attention isdirected to FIG. 18 where the control panel or console 152 is shown ingreater detail. The control panel includes a front face 640 having aseries of lights, switches, dials and meters thereon. Considering firstthe lights used on the face 640 of the control panel, there is a PowerOn light 642 connected across the output of the 48 volt DC power supply566. This light indicates that AC power is being supplied to themachine, that the power supply fuse circuit is working and that there isan output from the 48 volt power supply 566.

An Occluded Vein light 644 is provided to give a flashing signal whenthe occluded vein sensor detects occlusion of the donors vein. Once theoccluded vein situation has been corrected, the operator depresses thePush For Reset switch to restore the light 644 to its off condition.

A Bubble Detector light 646 is provided to flash on and off when thebubble detector unit 122 senses a particular volume of air in the returnline 92 leading back to the donor 50. The light 646 will continue toflash until the bubble detector collecting receptacle 600 is voided ofthe collected air by per-

1. A continuous flow blood separator comprising: means for separatingwhole blood into at least two fractional components; a source of wholeblood; supply means establishing continuous communication between saidsource of whole blood and said separating means to thereby provide wholeblood to be separated, said supply means including receptacle meanshaving an inlet means for receiving old blood from said source and anoutlet means for discharging said blood to said separating means; firstpump means for conveying said whole blood from said source to said inletmeans; weight sensing means coupled with said receptacle means, a signalmeans initiated by said weight sensing means and responsive topredetermined weight conditions of said receptacle means, said weightsensing means being controllably coupled with said first pump meanswhereby said signal means controls the operation of said pump means,whereby said first pump means may be operated intermittently orcontinuously; and return means establishing continuous communicationbetween said separating means and the source of whole blood to return atleast one of said separated fractional components from said separatingmeans to said source of whole blood.
 2. A continuous flow bloodseparator as defined in claim 1 wherein said supply means furtherincludes means for admixing an anti-coagulant with said whole bloodbefore the same is supplied to said separating means.
 3. A continuousflow blood separator as defined in claim 2 wherein said admixing meansis a second pump means.
 4. A continuous flow blood separator as definedin claim 3 wherein said first and second pump means operate at apreselected ratio to thereby control the respective whole blood andanti-coagulant flow rates.
 5. A continuous flow blood separator asdefined in claim 1 wherein said return means includes a bubble detectingand removing means to assure that any fractional component returned tosaid source is free of air bubbles.
 6. A continuous flow blood separatoras defined in claim 1 wherein said return means includes reheating meansfor heating a returning fractional component to substantially the sametemperature as that of the whole blood at said source.
 7. A continuousflow blood separator as defined in claim 1 wherein said separating meansseparates said whole blood into three fractions including red cells,white cells and plasma, and wherein said return means returns said redcells and at least a portion of said plasma to said source.
 8. Acontinuous flow blood separator comprising: means for separating wholeblood into at least the fractional components; a source of whole blood;supply means establishing continuous communication between said sourceof whole blood and said separating means to thereby provide whole bloodto be separated; and return means establishing continuous communicationbetween said separating means and the source of whole blood to return atleast one of said separated fractional components from said separatingmeans to said source of whole blood; said separating means including acentrifuge means and means for driving said centrifuge means; saidcentrifuge means including an outer casing means engaged with saiddriving means, an inner member disposed within said outer casing meansin spaced relation thereto, said outer casing means and said innermember thereby forming a confined chamber radially displaced from theaxis of rotation of said centrifuge means into which whole blood can beintroduced, said confined chamber being formed by the space between saidinner member and said outer casing means; passage means in said innermember communicating between said supply means and said confined chamberto supply whole blood to said confined chamber, said passage means beingcoaxial with said axis of rotation; and a cover means engaged with saidouter casing means and said inner member, said cover means includinginlet aperture means in communication with said passage means to admitwhole blood, and outlet port means communicating with said confinedchamber and said return means to permit at least one of said separatedfractions to be returned to said source, said outlet port meanscommunicating with said confined chamber at least at two differentseparation levels therewithin whereby one of said outlet port means isadapted to receive one separated fraction and another outlet port meansis adapted to receive a different separated fraction; said separatingmeans further includes seal means having a fixed portion and a rotatingportion, said rotating portion being coupled with said cover means, saidseal means further including a plurality of apertures therein, at leastone of said aperture communicating between said supply means and saidinlet aperture means, and at least two other apertures communicatingbetween said return means and said outlet port means, said fixed portionand said rotating portion each having a planar face, said planar facesbeing in abutting contact with one another to form an interface, atleast one of said planar faces having at least two groove means therein,each of said groove means forming a channel at said interface, saidchannels communicating with said outlet port means and said otherapertures, said channels being concentrically arranged about said axisof rotation, and pressure applying means engaged with said fixed portionto maintain said fixed portion pressed against said rotating portion. 9.A continuous flow blood separator comprising: means for separating wholeblood into at least two fractional components; a source of whole blood;supply means establishing continuous communication between said sourceof whole blood and said separating means to thereby provide whole bloodto be separated; return means establishing continuous communicationbetween said separating means and the source of whole blood to return atleast one of said separated fractional components from said separatingmeans to said source of whole blood; said return means including atleast two pump means to permit individual pumping of said fractionalcomponents from said separating means; said return means furtherincluding a pair of counteracting valves, which, in one positionrecombine one fractional component with another, and which, in anopposite position return said one fractional component to said supplymeans.